|By 1956 the large four cylinder engine was due to be replaced when BMC decided to rationalise its engine range into the three types, the A-series of 850cc, B-series of 1,500cc and C-series of 2,600 cc. The C-series engine, displacing 2,639 cc. would power the Austin A90 and Wolseley 6/90 and was proposed as the replacement for use in the Austin-Healey. It was actually developed by Morris not Austin, whose engineers were disparaging about its performance compared to their own big four.|
To accommodate the bigger engine a bonnet scoop was added to clear the radiator which was now farther forward. In addition, after pondering the marketing issues Donald Healey decided to add the two small jump seats in the back, in order to widen the car's appeal. This necessitated 2" being added to the chassis.